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Chantix Side Effects

Generic name: varenicline

Medically reviewed by Drugs.com. Last updated on Jul 13, 2024.

Note: This document provides detailed information about Chantix Side Effects associated with varenicline. Some dosage forms listed on this page may not apply specifically to the brand name Chantix.

Applies to varenicline: oral tablet.

Other dosage forms:

Common side effects of Chantix

Some side effects of varenicline may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • abnormal dreams
  • absence of menstruation
  • change in taste
  • diarrhea
  • difficulty having a bowel movement
  • difficulty in moving
  • excess air or gas in the stomach or bowels
  • joint pain or swelling
  • lack or loss of strength
  • loss of taste
  • muscle stiffness
  • painful menstruation
  • passing gas
  • toothache
  • trouble sleeping

Less common

  • belching
  • body aches or pain
  • burning, dry, or itching eyes
  • continuing ringing or buzzing or other unexplained noise in the ears
  • decreased interest in sexual intercourse
  • discharge, excessive tearing
  • ear congestion
  • feeling of constant movement of self or surroundings
  • feeling of warmth
  • hearing loss
  • inability to have or keep an erection
  • increased appetite
  • increased urge to urinate during the night
  • loss in sexual ability, desire, drive, or performance
  • loss of voice
  • nightmares
  • redness in the joints
  • redness of the face, neck, arms and occasionally, upper chest
  • redness, pain, swelling of the eye, eyelid, or inner lining of the eyelid
  • sensation of spinning
  • sleepiness or unusual drowsiness
  • sneezing
  • sore throat
  • stomach discomfort
  • stuffy or runny nose
  • transient, mild, pleasant aromatic odor
  • trouble concentrating
  • waking to urinate at night

Rare

  • change in color vision
  • difficulty seeing at night
  • increased sensitivity of the eyes to sunlight
  • night blindness
  • seeing floating dark spots or material before the eyes

Serious side effects of Chantix

Along with its needed effects, varenicline (the active ingredient contained in Chantix) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking varenicline:

Less common

  • anxiety
  • black, tarry stools
  • bloating or swelling of the face, arms, hands, lower legs, or feet
  • bloody stools
  • blurred vision
  • burning feeling in the chest or stomach
  • chest pain or discomfort
  • chills
  • cold hands and feet
  • cold sweats
  • confusion
  • cool, pale skin cough
  • deep or fast breathing with dizziness
  • difficult or labored breathing
  • dizziness
  • dry mouth
  • fainting
  • fast, pounding, or irregular heartbeat or pulse
  • flushed, dry skin
  • fruit-like breath odor
  • headache
  • headache, severe and throbbing
  • increased hunger
  • increased thirst
  • increased urination
  • indigestion
  • loss of consciousness
  • nausea
  • nervousness
  • nightmares
  • noisy breathing
  • nosebleed
  • numbness of the feet, hands and around the mouth
  • pain or discomfort in the arms, jaw, back, or neck
  • pale skin
  • pounding in the ears
  • rapid weight gain
  • seizures
  • shakiness
  • slow heartbeat
  • slurred speech
  • stomach pain or upset
  • sweating
  • swollen, painful, or tender lymph glands in the neck, armpit, or groin
  • tenderness in the stomach area
  • tightness in the chest
  • tingling of the hands or feet
  • tremor
  • troubled breathing with exertion
  • unexplained weight loss
  • unusual bleeding or bruising
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
  • unusual weight gain or loss
  • vomiting
  • vomiting of blood or material that looks like coffee grounds

Rare

  • agitation
  • bleeding gums
  • bloating
  • blood in the urine or stools
  • constipation
  • dark urine
  • decrease in height
  • decreased awareness or responsiveness
  • difficulty in swallowing
  • eye pain
  • feeling of fullness
  • fever
  • frequent urination
  • general feeling of illness
  • heartburn
  • hostility
  • increased sensitivity of the skin to sunlight
  • increased volume of pale, dilute urine
  • irritability
  • itching, skin rash
  • loss of appetite
  • mood changes
  • muscle pain, cramps, or twitching
  • numbness or tingling in the hands, feet, or lips
  • pain or burning in the throat
  • pains in the stomach, side, or abdomen, possibly radiating to the back
  • pinpoint red spots on the skin
  • red, scaling, or crusted skin
  • redness or other discoloration of the skin
  • severe sleepiness
  • severe stomach pain
  • severe sunburn
  • sores, ulcers, or white spots on the lips, tongue, or inside the mouth
  • tenderness, pain, swelling, warmth, skin discoloration, and prominent superficial veins over the affected area
  • uncontrolled eye movements
  • yellow eyes or skin

Incidence not known

  • anger
  • anxiety
  • behavior changes
  • discouragement
  • feeling sad or empty
  • feelings of panic
  • irregular heartbeat
  • loss of interest or pleasure
  • mood swings
  • restlessness
  • seeing, hearing, or feeling things that are not there
  • sleepwalking
  • thoughts of killing oneself

For healthcare professionals

Applies to varenicline: nasal spray, oral tablet.

General

The most commonly reported side effects included nausea, headache, insomnia, and abnormal dreams.[Ref]

Psychiatric

Gastrointestinal

Nervous system

Respiratory

Local

Cardiovascular

Metabolic

Musculoskeletal

Other

Dermatologic

Genitourinary

Immunologic

Hepatic

Ocular

Hematologic

Endocrine

Renal

Hypersensitivity

References

1. (2006) "Product Information. Chantix (varenicline)." Pfizer U.S. Pharmaceuticals Group

2. Cerner Multum, Inc. "UK Summary of Product Characteristics."

3. Cerner Multum, Inc. "Australian Product Information."

Frequently asked questions

Further information

Chantix side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.